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Our Team
Shaun P. O'Neill, CPA, CFE, CFF
Shaun P. O'Neill, CPA, CFE, CFF
Shaun P. O'Neill, CPA, CFE, CFF
Healthcare Fraud Prevention & Program Integrity Leader
Shaun O'Neill is a nationally recognized industry leader in combating health care fraud, waste, and abuse, renowned for his strong business acumen and unique ability to navigate the complex healthcare environment. He architects cutting-edge solutions for state insurance fraud units a
Healthcare Fraud Prevention & Program Integrity Leader
Shaun O'Neill is a nationally recognized industry leader in combating health care fraud, waste, and abuse, renowned for his strong business acumen and unique ability to navigate the complex healthcare environment. He architects cutting-edge solutions for state insurance fraud units and other clients, translating his deep experience into effective, real-world results. Throughout his career, Shaun has overseen some of the largest and most complex healthcare fraud cases in U.S. history. His work has led to the recovery of hundreds of millions of dollars and the implementation of systemic reforms across Medicaid and Medicare.
This expertise is built upon a distinguished 23-year career with the FBI, where he investigated a wide range of sophisticated criminal enterprises, including white-collar crime, public corruption, and organized crime. He culminated his FBI service by supervising a specialized squad of Agents and Analysts investigating health care fraud. Shaun co-founded the Greater Palm Beach Health Care Fraud Task Force and was instrumental in creating the groundbreaking Medicare Strike Force prosecution model—a strategy that fundamentally changed how the U.S. government combats systemic fraud. He continues to support public and private sector efforts to strengthen program integrity, enhance provider screening, and ensure taxpayer dollars are protected from abuse.
Shaun holds a Bachelor’s Degree in Economics and is a Certified Public Accountant (CPA), a Certified Fraud Examiner (CFE), and is Certified in Financial Forensics (CFF). As a sought-after speaker at national conferences, he continues to shape the industry's approach to fraud detection and prevention.
A. Marie Villafaña, JD, CFE
Shaun P. O'Neill, CPA, CFE, CFF
Shaun P. O'Neill, CPA, CFE, CFF
Marie comes to us after prosecuting complex criminal cases for over twenty years as an Assistant United States Attorney and serving as a Supervisory Administrative Law Judge with HHS. Her record speaks for itself.
For over 20 years, Marie served as an Assistant United States Attorney in the Southern District of Florida, investigating and
Marie comes to us after prosecuting complex criminal cases for over twenty years as an Assistant United States Attorney and serving as a Supervisory Administrative Law Judge with HHS. Her record speaks for itself.
For over 20 years, Marie served as an Assistant United States Attorney in the Southern District of Florida, investigating and prosecuting white collar crimes, human trafficking, child exploitation, narcotics, organized crime, and violent crimes. Marie served as the U.S. Attorney’s Office’s liaison to the Greater Palm Beach Health Care Fraud Task Force and the District’s first Project Safe Childhood Coordinator. Marie also served as a Supervisory Administrative Law Judge with the Office of Medicare Hearings and Appeals within the U.S. Department of Health and Human Services, adjudicating level three appeals involving Medicare Parts A, B, C, and D.
Prior to entering public service, Marie worked as a Litigation Associate with Morrison & Foerster in San Francisco and an Intellectual Property Litigation associate with Dorsey & Whitney in Minneapolis and London.
Marie’s work has been recognized inside and outside the Department of Justice. In 2011, she received the National Crime Victims’ Rights Service Award from the Department of Justice, and in 2015, she received the Director’s Award, the highest honor given by the Executive Office of U.S. Attorneys. The same year, she received the Attorney General’s Award for Fraud Prevention. Marie also has been named the Prosecutor of the Year by the Florida Insurance Fraud Education Committee and the Coalition Against Insurance Fraud. In 2017, her team received the National Healthcare Anti-Fraud Association Investigation of the Year Award, and in 2018, she received the Council of the Inspectors General on Integrity and Efficiency Award. In 2019, she was named the Insurance Fraud Fighter of the Year by the Florida Insurance Fraud Education Committee. Marie also has been featured on American Greed: Florida Rehab Gone Wild.
Marie graduated from Cornell University with a B.A. in Economics in May 1989, and a J.D. from the University of California at Berkeley School of Law in 1993. In 2017, she completed a Health Care Compliance Certificate Program at Mitchell Hamline School of Law. Marie is a Certified Fraud Examiner (CFE).
Maribel A. Arellano, CPA, CAMS
Maribel A. Arellano, CPA, CAMS
Maribel A. Arellano, CPA, CAMS
Maribel joins the PRISM team bringing 34 years of experience as a Financial Auditor and Investigative Analyst for the Office of Inspector General’s Department of Health and Human Services, U.S. Attorney’s Office, and Internal Revenue Service. During Maribel’s career she worked both Civil and Criminal Investigations involving economic crim
Maribel joins the PRISM team bringing 34 years of experience as a Financial Auditor and Investigative Analyst for the Office of Inspector General’s Department of Health and Human Services, U.S. Attorney’s Office, and Internal Revenue Service. During Maribel’s career she worked both Civil and Criminal Investigations involving economic crimes involving healthcare fraud, bank fraud, mortgage fraud, securities fraud, mail fraud, tax fraud, as well as human trafficking. During her investigations, Maribel worked extensively with the Financial Crimes Enforcement Network (FinCen), Center of Medicaid and Medicare Services (CMS), Federal Bureau of Investigations, (FBI) and other Federal, State, and Local law enforcement agencies. Prior to her retirement from Federal service, Maribel mentored and trained all incoming professionals assigned to the investigative analyst unit and assisted analysts and law enforcement agents in other regions across the nation with the use of financial software programs and public and private Federal and State databases.
Maribel has been recognized on numerous occasions for her attention to detail throughout her career. In 2016 she was recognized for the “Investigation of the Year Award” Honorable Mention from the National Health Care Anti-Fraud Association (NHCAA). She was also recognized in 2016 with the Inspector General’s Cooperative Achievement Award in “recognition of collaborative efforts and commitment to fighting health care fraud in South Florida and across the globe”.
Maribel holds a Master’s Degree in Accounting from St. Thomas University, and a Bachelor’s Degree in Business Administration from University of Miami. She is a Certified Public Accountant (CPA) and holds the designation of Certified Anti-Money Laundering Specialist (CAMS).
Selby Smith
Maribel A. Arellano, CPA, CAMS
Maribel A. Arellano, CPA, CAMS
Selby joins the expanding PRISM team and will provide a range of consulting services based on his years of leadership and investigative experiences. He retired as an Assistant Special in Charge with the U.S. Drug Enforcement Administration (DEA). He went on to serve as the Assistant Chief of Police for Spokane, Washington Police Departmen
Selby joins the expanding PRISM team and will provide a range of consulting services based on his years of leadership and investigative experiences. He retired as an Assistant Special in Charge with the U.S. Drug Enforcement Administration (DEA). He went on to serve as the Assistant Chief of Police for Spokane, Washington Police Department. Selby is also retired as a Major in the U.S. Air Force Reserves, Security Forces. Selby utilized his extensive investigative experience on Healthcare Fraud investigations as a CMS contract investigator for the past eight years.
Selby’s experience includes international criminal investigations, management, and use of cooperating sources (Informants), international and domestic money laundering, narcotic investigations, asset forfeiture, drug diversion investigations, internal investigations, EEO investigations, risk mitigation in enforcement operations, and internal policy reviews. Selby was operational in multiple countries to include Islamabad, Pakistan and Kabul, Afghanistan. As an Assistant Chief of Police, he was the Chief of Detectives, managing all aspects of the detective’s bureau from drugs to major crimes, domestic violence to property crimes. As a healthcare fraud investigator, Selby investigated fraud cases involving Part C and Part D of Medicare, such as DME, upcoding, unbundling, pharmacy fraud, telemarketing, identity theft and phantom billing.
Selby’s leadership experience resonates from the military to law enforcement to fraud investigations. He has spent countless hours honing his skills in the management of others which has led to the creation of several highly successful teams.
Selby is a published author on Human Intelligence, aka Informants How to Identification and Manage. Selby teaches the use and management of human intelligence assets to local, state, and federal law enforcement officers. Selby also teaches Risk Mitigation in Law Enforcement Operations such as search/arrest warrants, undercover operations, and street operations.
Selby holds a Bachelor’s Degree in Criminal Justice and a Master’s Degree in Public Administration. Selby has testified in multiple trials as an expert witness on drug trafficking and money laundering.